The invention relates to a device for injecting a gaseous fuel into an internal combustion engine with several cylinders, comprising a vaporizer/pressure regulator, metering means for supplying the fuel from the vaporizer/pressure regulator to the inlet of each cylinder, as well as an injection valve provided in each pipe near the inlet of each cylinder, for maintaining a constant pressure between the metering means and each inlet. Such a device is known from Dutch Application 8,600,611. This device has a manifold header which is connected at one side to a central supply pipe supplied by the metering means, and, at the other side, is connected to a number of supply pipes each running to the inlet of a cylinder. A pressure regulating valve, for the purpose of making the pressure upstream of the valve independent of the pressure downstream of the valve, is also provided between the metering means and the manifold header.
This known device has various disadvantages. Although the pressure regulating valve used here protects the supply pipe lying upstream thereof as regards sudden pressure changes in the inlet manifold of the engine, response problems can still occur as a result of pressure equalization in the pipes situated between the pressure regulating valve and the inlet manifold.
It is also found to be difficult to supply all cylinders uniformly. The supply of the cylinders far away from the manifold header often remains lower than that of those closer to it.